The attorney general of the central-western Mexican state of Michoacan said a priest was found shot dead Sunday, becoming the third cleric to be kidnapped and killed in the country within a week.

Authorities said Jose Alfredo Lopez Guillen, who had been missing since late last Monday, was found dead on a highway. Autopsy results indicated the priest was likely killed five days before his body was found.

The killing came less than a week after two other priests were kidnapped from their church in Poza Rica and later found dead in the eastern state of Veracruz.

While there has been no claim of responsibility and no motive has been given for the killings, some priests in Mexico over the years have denounced drug gangs and their violence.

Reports say at least 31 priests have been murdered after a decade of drug violence in the country.

The archdiocese has released a statement urging investigators to solve the latest crime. “We lament these violent acts and the insecurity in our state,” the statement said.